Rita Levi-Montalcini, who has died aged 103, overcame racial and sexual prejudice to become a leading neurobiologist and one of the handful of women scientists to win a Nobel Prize.

Her triumph came in 1986, when she shared the Nobel Prize in physiology or medicine with her student, the biochemist Stanley Cohen, for their contributions to the understanding of growth factors in human development.

By the 1950s, the pattern of cell growth and differentiation had long been established, and scientists knew that the addition of blood or organ extracts to cells in culture resulted in their successful growth. They did not know, however, the identity of the active substances, just as cancer researchers understood little of the unregulated growth of tumour cells.

In 1952, Rita Levi-Montalcini found that when tumours from mice were transplanted to chick embryos, they induced potent growth of the chick embryo nervous system . She concluded that the tumour released a nerve growth-promoting factor (NGF) which had a selective action on certain types of nerve cells.

Following this discovery, she began to measure the effect of NGF on cells in culture, and discovered that a sensory or sympathetic nerve cell reacted within 30 seconds of the addition of minute quantities of NGF. Just one billionth part of a gram of NGF per millilitre of culture medium exerted a potent growth-promoting effect.

In 1953 the biochemist Stanley Cohen joined her research group at Washington University, St Louis, and together they purified a nerve growth-promoting extract. Rita Levi-Montalcini’s discovery improved scientific understanding of the processes involved in certain physical malformations and diseases. It has led to improved therapeutic agents and could be central to eventual treatments for diseases such as multiple sclerosis or Alzheimer’s as well as psychiatric disorders such as depression or anorexia.

Rita Levi-Montalcini was born, with her twin sister Paola, in Turin on April 22 1909, the youngest of four children. Her father, Adamo Levi, was an electrical engineer and mathematician, and her mother, Adele Montalcini, a talented painter. Their elder brother, Gino, would become a prominent Italian architect and professor at the University of Turin.

Though the family was cultured, Rita’s father took a traditional view of a woman’s place and decided that his three daughters should not go to university. But Rita was convinced she could not be content with a merely domestic role and, at the age of 20, begged her father to be allowed to try for university. Eventually he relented and within eight months she had rectified her deficiencies in Latin, Greek and Mathematics, graduated from high school, and enrolled at the medical school in Turin, where she studied under the histologist Giuseppe Levi.

In 1936 she graduated with a summa cum laude degree in Medicine and Surgery, and began postgraduate work in neurology and psychiatry. But that year, Mussolini issued the Manifesto per la Difesa della Razza, signed by 10 Italian scientists, which called for laws barring academic and professional careers to non-Aryan citizens. She therefore left Italy for Belgium, where she worked as a guest of a neurological institute in Brussels. In 1940, on the eve of the German invasion of Belgium, she returned to the relative safety of Turin.

Realising it would not be possible to pursue her scientific interests openly, Rita Levi-Montalcini built a small research unit in her bedroom. By this time, inspired by a 1934 article by Viktor Hamburger reporting on the effects of limb amputation in chick embryos, she had become interested in the mechanisms controlling the development of the vertebrate nervous system. She had barely begun work when her former teacher, Giuseppe Levi, who had also escaped from Belgium, returned to Turin and joined her in her work.

Forced to leave Turin by the heavy Allied bombing of the city in 1941, she moved her laboratory to a cottage in Piemonte. But the invasion of Italy by the German Army in 1943 forced her to move again and she remained in hiding in Florence until the Allies liberated the city in August 1944. She was then taken on by the Allied armies as a volunteer physician and assigned to a refugee camp, where she had to treat cases of typhoid and other infectious diseases.

When the war ended she returned with her family to Turin and resumed her academic career at the University. In 1947 she received an invitation from Viktor Hamburger to join him at Washington University, St Louis, where he was a professor. She planned to remain in America for a year but, as a result of the success of her research, decided to postpone her return.

She continued her research on NGF for some 30 years. In 1956 she was appointed Associate Professor and in 1958 full Professor of Neurobiology at Washington University, a position she held until her retirement in 1977. In 1962 she established a research unit in Rome, and from then on, she divided her time between Italy and America. From 1969 to 1978 she was Director of the Institute of Cell Biology of the Italian National Council of Research.

After her retirement in 1979 she became an emeritus professor at the Institute, and from 1989 to 1995, by now well into her eighties, she worked at the Italian National Council of Research Institute of Neurobiology, testing new hypotheses on the action of NGF.

From 1993 to 1998 she was President of the Institute of the Italian Encyclopaedia. She was the author of numerous scientific publications, four bestsellers, and a short autobiography, In Praise of Imperfection. In 1992 she created, together with her twin sister, the Levi-Montalcini Foundation, in memory of their father, to assist young people in the difficult choices regarding their fields of study.

Rita Levi-Montalcini was a member of many scientific academies, including the Accademia Nazionale dei Lincei, the Pontifical Academy, the Accademia delle Scienze, the American National Academy of Sciences, and the Royal Society.